Phase controlled oscillating system



Feb. 11, 1930. s. N. BARUCH 2,030,090

PHASE CONTROLLED OSCILLATING SYSTEM Original Filed April 18, 1929 INVENTOR 6Y0-r/V. 6/1/9001 v /QM ATTORNEY Patented Feb. 11, 1936 OFFICE PHASE CONTROLLED OSCILLATING SYSTEM Sydney N. Baruch, New York, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Refiled for abandoned application Serial No. 333,901, April 18, 1929. This application June 22, 1934, Serial No. 731,819

2 Claims.

general use; also, to control the output of an electronic tube oscillating system. A further object of the invention resides in the provision of a novel modulating member for use with the system.

In carrying out the invention, use is made of two closed circuits each embodying an electronic tube, inductance, capacitance, and suitable sources of A- and B-potential, both circuits being caused to oscillate and one being coupled to the grid of the other, while the outputs of both of said circuits are associated with a suitable pick-up or output circuit common thereto. In addition, means are provided for varying or modulating the frequency of the grid-coupled circuit as by changing the constants of said circuit, the two oscillating circuits initially being arranged so that their respective oscillations are not in phase, being from 90-180 apart.

The nature of the invention, however, will best be understood when described in connection with the accompanying drawing, in which:

Figure 1 is a diagrammatic representation of the circuits employed in the novel system, and the manner of interconnecting the same.

Figure 2 is a longitudinal section of a modulating device suitable for use in the novel system, with microphone connected thereto; and Figure 3 is a. transverse section thereof taken on the line 33 of Figure 2, looking in the direction of the arrows.

Referring to the drawing, Ill designates an oscillating circuit comprising, an electronic tube such as shown embodying the grid ll, hot electrode or filament l2 and cold electrode or plate I3, with suitable A-battery l4 and B-battery l5 connected thereto in the usual manner. The plate circuit includes an inductance, for example, in the nature of an adjustable honeycomb coil 16 and across the same is connected a condenser l1, while the filament I2 is connected to the grid I I through the resistance l8 and inductance IS. A suitable frequency controlled device I9, as for The invention relates to a method of and.

example, a piezo-electric crystal (quartz), may also be shunted across the grid circuit to substantially fix the frequency of oscillation of circuit ID.

The other circuit 2!! likewise comprises a tube embodying the grid 2|, hot electrode 22 and cold electrode 23, with suitable A- and B-batteries 24 and 25, respectively, and an inductance 26 in. the plate circuit, which inductance may likewise be an adjustable honeycomb coil. A Variable condenser 21 is connected between the anode 25 and cathode 22, and the hot electrode 22 is connected to the grid 2| through a resistance 28 and a coupling inductance 29 with condenser 30 across the same. Coupling inductance 29, moreover, is associated with an inductance 3| included in the plate circuit of the oscillating circuit 10, whereby the respective oscillations of the two circuits may, by a proper choice of the circuit constants, be arranged to be out of phase from l-90, and thus completely or partially suppress the combined outputs of the two said circuits.

However, if the constants of the oscillation circuit 20 which is grid-coupled at 29, 30 be altered,

the phase relationship mentioned above is immediately disturbed and a change in the power output from the two oscillators results. This output may be picked up by an additional honeycomb coil 35 associated with the two coils l6 and 26. Energy may be transferred to 35 from either one or from both of the coils l6 and 26 which, furthermore, are adjustable for the purpose of equalizing the flux between the same and said coil 35. Coil 35, through the outgoing leads 3% thereof, will thus supply for any desired purpose current from said oscillating circuits; and

the amount thereof, as in initially setting the circuits, may be indicated upon a suitable measuring instrument 3'! which may be connected in said circuit.

In utilizing this system for the amplification of smalll powers or other physical changes, it is necessary merely to upset the constants of the grid-coupled circuit 20 and vary thereby the relationship between the oscillations in the two oscillating circuits l0 and 20 thereby varying the phase of the oscillations fed to inductance 35. As one means of accomplishing this result, I have indicated a variable condenser 40 connected across the condenser 30 of the oscillating circuit 20. I have also devised for this purpose a very sensitive capacitance changing member, reference being had more particularly to Figures 2 and 3 of the drawing. As indicated therein, a barrel or cylindrical device 4| of insulating material is provided with an internal thread from one end and into which may be screwed a metallic plug 42 from which a lead 43 extends outwardly for connnection across condenser 30. The other end of the barrel 4| is closed by the cap or housing 45 of a telephone receiver having its diaphragm 46 connected through lead 41 with the condenser 36. Thedevice of Figures 2 and 3 may replace the variable condenser 40 of Figure 1.

The diaphragm 46 may be actuated in any man ner. For example, it may be actuated by a microphone 48 to vibrate toward and away from the metallic plug 42 in accordance with sounds or other impulses impressed on 48. These vibrations will thus change the thickness of the dielectric (air) between the two metal elements, namely the plug 42 and the diaphragm 46 itself, making a very sensitive condenser. The initial capacity of this condenser can be adjusted by varying the position, for example, of the plug 42 in said barrel as by screwing in or out the same .(an adjusted position being indicated by the position shown in dotted lines); and this affords also a means for adjusting the original setting of the oscillating circuits in conjunction with the indications of instrument 3! of the outputline.

, Having thus described my invention and the operation thereof what I claim is:

1. A signalling system comprising, an oscillation generator of the constant frequency type including a thermionic tube having anode, cathode and'control grid, a frequency determining circuit connected between the control grid and cathode of said tube, an output circuit connected between theranode and cathode of said tube, a second oscillation generator comprising a second thermionic tube having anode, cathode and control grid, a circuit including reactances coupled between the control grid and cathode of said second named tube, one of said reactances being variable at signal frequency, an output circuit connected between the anode and cathode of said last named tube, a load circuit variably coupled to both of said output circuits, and a reactance coupling the output circuit of said first named cuit including an inductance and a capacity in parallel between the control grid and cathode of said second named tube, a coupling between" said last named inductance and one of the in-" ductances in the output circuit of said first named tube, an inductance connected between the anode and cathode of said second named tube, a utilization circuit including an inductance'coupled to the inductance in the output circuit of said'sec ond named tube and to an inductance in the output circuit of said first namedtube' and a variable reactance connected in parallel with a portion of the circuit connected with the control grid and cathode of the second namedtube.

SYDNEY N. BAR-UCH' 

